Could someone more knowledgeable explain what the practical effect of this license change is? As far as I can see, there isn't much of a difference?
I was reading of an exploit where an organisation is publishing photos under the 3.0 licence, searching for minor infractions and then extorting random bloggers and businesses for infringement. I believe the 4.0 licence addresses this by allowing users to fix a faulty attribution within a reasonable time.